Apparatus for separating coal



May 11 1926. 1,584,017

M. W. DITTO APPARATUS FOR SEPARATING GOA-L Filed June 2. 1922 PatentedMay 11, 1926.

UNITED STATES MARVIN W. DITTO, OF NEW YORKQN. Y.

' AIPPARATUS FOR SEPARATING CQAL.

Application filed June 2, 1922. Serial No. 565,381.

My invention relates to a novel means for separating coal from itsimpurities.

While the invention herein is described specifically as relating to theseparation of coal from its impurities, it is to be understood that theinvention is not limited to coal nor any other specific material but maybe applied to grading, separatingv or class1- fying of any desiredmaterial. a

In the matter of preparing coke for metallurgical and other purposes, itis desirable to exclude as much of the impurities such as slate, earthymaterial and the like as is possible. Primarily a good grade of coal isemployedand this is freed as largely as possible from the large piecesof slate and earthy material which can conveniently be by verticalvibrations of relatively picked out, This leaves the smaller particlesof impurities and also leaves such 1mpurities as are left clin 'ng tolumps of coal. The coal is then groun orcrushed to a fine ness capableof passing a /g-IIlOll mesh screen. The crushing of the coal releasesmany of the smaller particles of slate and the like which adhered to thelumps of coal, and it is then possible to remove "a large portion of theimpurities.

I am aware that the broad result of soparating out one constituent of amass from? another or others is old, but heretofore, such separationparticularly in the case of coal, has been secured only at theexpenditure of a relatively great amount of power and consequentexpense, or at some equally serious disadvantage.

My invention aims broadly to provide an improved apparatus forseparation of coal andil other materials to be graded or separate I Theparticular manner in which I accomplish this is through the use ofareciprocatory riffle top which is activated or sensitized highfrequency.

In order to a quaint those skilled in the art withthe inner ofconstructing, operating and practicing my invention, I shall nowdescribe in connection with the accompanying drawings a specificembodiment of the invention. In the accompanying draw-- ings Figure 1 isa diagrammatic plan view of a separating table employing my invention;

Fig. 2 is a further diagrammatic illuss table with either aplane or athe way, the partlcle 1, would 1n 2. series tration indicating moreparticularly themanner of use of the same;

Fig. 3 is a section taken on the line of 3-3 of Fig. 2, and

Fig, 4 is an isometric view of a modified device embodying my invention.

Figure 1 shows diagrammatically the topof a table or riflie suitable forpracticing my invention. The table top A B C D provides .a plane surfacewhich may in practice he of suitable dimensions such as 6 feet wide by12 feet long, resting upon casters or swinging links as is wellunderstood in the art, and moved longitudinally by an eccentric headmot-ion which is indicated at 5 for imparting to the table a back andforward movement within adjustable limits as indicated by the arrows 6,7.

The table is so mounted that it may be adjustably inclined in two.directions as indicated in Figure 1 by the arrows 8 and 9, Preferablythe point C, which is the lowerright hand corner in the 'figure, has themaximum depression below a horizontal plane, point B being higher than Cand point D being higher than point B and point A being uppermost.

Broadly speaking, so much of the arrangement as. I have described, isknown in the are and has been employed generally with water rinningoverthe table to separate metal fr bin earthy matter or gangue in recoveringmetallic values from ores, or in connection with other processes,

In the separation of coal from its impurities, assume that we place twoparticles, namely, a heavier particlel of slate or earthy material, anda lighter particle 2 of coal upon the table side by side as shown, and

I the table the reciprocatory motion from the eccentric head mechanism5. Assuming that the particle 2 were not in imp art to of smallexcursions as indicated by the scalwith 18 and condition over that shownin Figure l is the result. As shown in Figure 1, the path of movement ofthe particle 1 intersects that dency will be ineffective on account ofinterference. Where water is employed, the lifting and lubricatingproperty of the water permits the particles to pass each other withrelatively great freedom. However, in the matter of separating coal fromits impurities it is undesirable to employ water since water isdifficult to remove from the coal except by direct evaporation, and thisinvolves a distinct loss in power, takes time and attention and makesthe matter of coking more difficult.

The essence of my invention is to activate these particles, as they moveacross the table, by a motion of vibration. In other words, I vibratethe table top vigorously at a high frequency so that the particles danceup and down and thereby have great freedom of motion with respect toeach other, both with respect to vertical movement to permit the heavierparticles .to sink to the bottom of the layer of material, and alsogreat freedom in a lateral direction to permit the heavier particles totravel longitudinally of the table at a greater rate than the lightercoal particles.

The invention may appear in a great variety of apparatus and thefundamental idea of activating or enlivening the layer of material may,if desired, be assisted by other means such for instance .asthe use ofliquids or fluids tending to levitate the particles onthe table top.This action of vertical vibration in connection with horizontal rifflingpermits of a great increase in capacity a consequent saving in power.

As shown in Figures 2 and 3,"the table is divided into three sections,13, 14 and 15, this table comprising a suitable framework, comprising.the back 16 and the sides 17 and partitions 21 and 22 with a metallicsheet in one or more sections stretched across the frame to form thetable top 23. This table top is of suitable sheet material capable ofwithstanding tension sufficient to make it vibratile in character. Thistop 23 thus becomes a member which may be readily vibrated like the headof a drum. ll provide means such as' the rapping device shown at 24 forvibrating the particular section of the 'head or top 23. In this case oflinks or arms 25 are pivoted loosely upon pins 26, these arms or linksbeing slotted Preferably the size and tension of the diaphragm isadjusted to correspond to the pitch of vibration of the striking orrapping arms 25.

In the adjacent compartment I have shown an electrically operatedvibratmg' mechanism comprising the solenoid winding 28' which isconnected'to a suitable source of current as shown at 29, this source ofcurrent being preferably of such a character as to provide a suitablealternatingcurrent of the desiredfrequency. A solenoid core 30 isadapted to strike the wear plate 31 fastened upon the bottom of thecorresponding section of the head 23. This solenoid core is moved in onedirection by the attraction of the solenoid winding 28 and is moved inthe opposite digection preferably by an adjustable spring such as shownat 32, this spring being placed under the desired tension by anadjustable compression screw 33. In accordance with the constructionherein shown, impulses of current may be employed.

In the third compartment I have ilhis- I q I, as itperforms the functionof activating suitable ends with division walls or As shown in Figure2 afeed box is proa number vided at 40 for feeding the material upon thetable top at the upper left hand corner of the same. This top isprovided with the upward flow adjustable riflles or ribs 41 which extendpreferably longitudinally of the table. The feed box is designed toprovide a uniform flow of pulverized or ground coal onto the head of thetable whereupon the material comes into violent agitation andsimultaneously is operated upon by the reciprocating action of the tablewhereby the heavier material, namely the slate, sand and otherimpurities are sifted through the coal, which is lighter, the heavierparticles traveling in contact with the table top longitudinally of theriflies and being discharged off the end of the table as indicated at 42between the guiding walls therein shown. The lighter material, namely,the coal, which has been displaced to the top of the table rolls morefreely down the lateral inclination, being less affected by thelongitudinal reciprocation of the table. Due to the vibratory action ofthe table in maintaining a very free flow of the heavier par ticles downtowards the table top, and an of the lighter particles above the same, ahigh speed of treatment and a very satisfactory degree of separation isattainable. The particles of coal are discharged off of the lowerlateral edge of the table between the walls or vanes 43.

This separation may be made while the material is completely dry, but itdoes not preclude theiuse of a fluid medium for as- 'si1s1ting in theseparation. l/Vater is genera y undesirable since it must be evaporatedoff and this takes a great deal of heat which does no particular good. Imay, however, assist in activating the material by the use of air, thisair being driven up through the table top itself, which table top isprovided with suitable openings same.

In Figure 4- I have shown a table top of this construction, in which, inaddition to the vibrating mechanism for vibrating the table top in adirection substantially at right angles to the plane of the top, Iprovide also fluid lubricating means (in this for permitting the case,air) which is fed into the various compartments 13, 14: and 15 throughthe openings 44, 45 and 46, the head of the table,

thatis, the diaphragm or top in this case being made of a foram'inoussheet placed under suitable tension so as to be easily vibrated by meanssuch as I have previously described. In this case the air which isforced through the foraminous table top assists in the segregation ofthe two types of particles by a tendency to levitate the which the airmay be discharged in minute streams through the material. The supply ofair which is required under this mode of operation is far less than thatwhich would be required to lubricate the particles past each other if nomechanical vibration of the table top were provided. That is to say, avery great velocity would be necessary to lift the particles whereasaccording to my improved method of operation the particles are lifted byrepeated contact with the vibrating surface, the air in this case merelyassisting in holding the particles suspended above the vibrating top byincreas ing the amplitude of vibration of these particles. It will beappreciated at once that the particles are driven upwardly by thevibrating surface, and that they are assisted in their upward travel bythe current of air which also retards their return to the table topwhereby a greater amplitude of vibration and a consequent greaterfreedom of the particles with respect to each other is secured. Thecombined effect of mechanical vibration and fluid flotation provides amethod of operation which is a great advance over the previous deviceswith which I am familiar.

In interpreting the frequency, it is desirable to take into account thecritical point for the vmaterial under treatment. The

range may lie between zero and sixty-thousand vibrations per minute.

I do not intend to be limited to the details shown or described.

I cla1m:

In combination, a table, said tablehaving a flexible diaphragm-like topnormally under tension, and permeable to the flotation fluid, butimpermeable to any of the material treated, said table being inclined invtwo directions with the corners successively one higher than theot-herand vice versa with the corners successively lower than the other,

means for simultaneously and independently vibrating areas of said tabletop vertically at the same and different amplittrdesand frequencies,means for .reciprocating the table substantially horizontally at a lowerfrequency, and means for causing an upward fluid flotationsupply throughthe, table top.

In witness whereof, I hereunto subscribe my name this 31st day of May,1922.

- MARVIN 1V. DI'ITO.

